1. Field of the Invention
The present invention is generally related to a waterjet maneuvering system for a marine vessel and, more particularly, to a system that uses three or more streams of water in a coordinated manner to maneuver a marine vessel into a desired position on a body of water.
2. Description of the Prior Art
Many different devices are known to those skilled in the art for maneuvering a marine vessel. Certain marine vessels, because of their size, can pose particularly difficult problems during docking procedures. Various kinds of bow thrusters, stern thrusters, and other auxiliary propulsion devices have been used in the past to assist in maneuvering large marine vessels.
U.S. Pat. No. 4,549,868, which issued to Lolly on Oct. 29, 1985, discloses a jet propulsion system for boats. The jet actuated boat propulsion device is provided for driving the boat in areas where hyacinth or other water vegetation exists, and which normally would foul the operation of an outboard or inboard motor. A water pump positioned in a well in the bottom of a boat and communicating with the water in which the boat is floating is connected through conduits to discharge a jet of water through a nozzle extending into the body of water in which the boat is floating. The jettisoned water is discharged into the body of water and exerts a jet action or thrust which drives the boat through the water. The difficulties which have heretofore been encountered in propelling boats in areas where hyacinth or other water plants exist have thus been virtually eliminated because the discharge pipe for the water being jettisoned projects into the body of water at an angle, and therefore the hyacinth and other water plants slip off the pipe for the jettisoned water and exerts a forward thrust on the boat from an area beneath the surface of the water in which the boat is floating. A modified form includes a motor driven pump connected to twin pipes, one of which is a water inlet and the other pipe is the jet pipe to drive the boat through the water.
U.S. Pat. No. 4,807,552, which issued to Fowler on Feb. 28, 1989, describes a small boat bow thruster. The thruster includes a port and starboard discharge nozzle forwardly mounted through the hull of the boat and above the waterline. Water from an inlet port located below the waterline of the boat is drawn by a pump through conduits to the discharge nozzles. The pump is a by-directional positive displacement pump which can feed either the starboard or port discharge nozzle depending on the direction of pump rotor rotation. The pump is powered by an electric motor capable of running in a normal or reverse mode and which is controlled by an activation switch manually operated. Water is discharged through the port or starboard nozzle above the waterline of the boat when the system is activated. The bow is thrust sideways in the direction opposite of the nozzle discharge allowing slow and controlled maneuvering of the boat in tight spaces.
U.S. Pat. No. 4,056,073, which issued to Dashew et al on Nov. 1, 1977, discloses a boat thruster which includes a diverter valve with an inlet connected to a water pump, a pair of outlets extending to either side of the boat, a valve mechanism for accurately controlling the amount of thrust obtained from both outlets, and a deflector positioned at each outlet. Each deflector is moveable between a first position wherein it allows sideward water discharge to thrust the bow to the side, and a second position where it directs water rearwardly to move the boat in a forward direction, or if required, to a third position to move the boat rearwardly.
U.S. Pat. No. 5,289,793, which issued to Aker on Mar. 1, 1994, discloses a heliconic thruster system for a marine vessel. The thruster system is provided for maneuvering or propulsion of a marine vessel through the use of directionally oriented waterjets discharged tangentially from a helical-conical flow chamber. The thruster system includes a high capacity pump for pumping water through a hull intake to the flow chamber with a substantial helical or swirling action. The water exists the flow chamber through one or more of a plurality of tangentially oriented discharge conduits having discharge nozzles for passage of high velocity waterjets through the hull, resulting in reaction forces used to maneuver or propel the vessel. Each discharge conduit includes a valve member moveable between open and closed positions for respectively permitting or preventing water flow to the associated nozzle.
U.S. Pat. No. 4,208,978, which issued to Eller on Jun. 24, 1980, describes a lateral thruster for a water vessel. The bow thruster comprises a submersible axial flow pumping unit mounted on the outside of the vessel at the bow to be raised to an inoperative position out of the water or lowered to an operative position in the water with its water flow axis perpendicular to the longitudinal centerline of the vessel. The pumping unit is reversible, and it includes a hydraulic motor and a pump impeller inside an annular housing provided with gate valves at its opposite ends. The gate valve at the discharge end restricts the flow there to increase the thrust produced by the pump. A directional control and a fluid pressure source for the hydraulic motor in the submersible pump unit are onboard the vessel.
U.S. Pat. No. 4,294,186, which issued to Wardell on Oct. 13, 1981, discloses a retractable bow thruster. The device comprises a main support housing which is secured to the hull of a vessel. An opening is made within the lower portion of the housing through the vessel hull to allow a thruster drive assembly to lower into operative position. The drive assembly includes an upper gear housing which mounts in a drive gear. The upper gear housing is pivotally mounted for rotation about the axis of rotation of the drive gear. The opposite end of the upper gear housing is pivotally attached to a vertically displaceable lower gear housing which mounts an idler gear and a propeller. The idler gear drives a ring gear disposed about the propeller. When the upper gear housing is moved about its pivot access, the lower gear housing moves vertically causing the propeller to move from a recessed position to an operative position below the bow of the boat to provide lateral thrust to the boat.
U.S. Pat. No. 5,522,335, which issued to Veronesi on Jun. 4, 1996, describes a combined azimuthing and tunnel auxiliary thruster powered by integral and a canned electrical motor. The thruster is intended for use by a marine vessel and includes a submersible propulsion unit which has a shroud with a propeller rotatably mounted therein. A canned electric motor is mounted between the propeller and the shroud for rotating the propeller to create thrust. A propulsion unit deploying and rotating mechanism is mounted on the hull and on the propulsion unit. The propulsion unit deploying and rotating mechanism is operable to extend the propulsion unit out of the hull and retract it into the hull and to rotate the propulsion unit to direct the thrust generated thereby in any direction when the thruster is in the deploy position. When the thruster is retracted, it is positioned with a tunnel extending transversely through the hull. Rotation of the propeller while in the retracted position generates laterally directed thrusts through the tunnel.
U.S. Pat. No. 5,282,763, which issued to Dixon on Feb. 1, 1994, describes a steerable bow thruster for swatch vessels. The bow thruster system is located substantially within the pontoons of a semisubmerged vessel exclusive of a rotating nozzle which is located on the upper side of the pontoons. The rotating nozzle can turn in any direction and allows the steerable bow thruster system to thrust forward, aft, side to side, and in any direction in between to allow the semisubmerged vessel to maneuver freely and within the assistance of the main engines. To minimize draft and to prevent ecological harm, the nozzles are installed on the top of the pontoons allowing the pontoons to act as a barrier to keep thrust wash from disturbing shallow ocean bottoms and reefs over which the vessel may be operating. The propeller means may be shrouded to prevent harm or injury is to swimmers who may be in the water. A rudder may also be coupled to the thruster nozzle to provide directional control for the semisubmerged vessel when it is underway at higher speeds. The nozzle of the propelling means may be located forward of the center of lateral resistance of the semisubmerged vessel.
U.S. Pat. No. 4,732,104, which issued to Roestenberg on Mar. 22, 1988, discloses a bow thruster that is pivotal and adapted to be adjustably pivoted about a stem of a boat, which enhances attainment of smooth, save docking of the boat, with better control, and minimal difficulty. The bow thruster comprises two propellers which, when spinning, thrust the bow of the boat to starboard or to port and a mechanism for pivoting the propellers about the stem of the boat. This pivoting mechanism comprises a pivoting arm coupled to the propeller unit and a gear train which, when activated, rotates the pivoting arm.
U.S. Pat. No. 5,642,684, which issued to Aker on Jul. 1, 1997, describes a thrust director unit for a marine vessel. The improved thrust director unit is provided for discharging a directionally adjustable waterjet flow from the hull of a marine vessel to generate a thrust reaction force for close quarter maneuvering and/or propulsion of the vessel. The unit comprises a thruster housing having an outlet through which the jet flow is discharged, wherein the outlet is defined by diverging fore-aft walls to permit angularly forward or rearward jet flow discharge for vessel propulsion. At least two deflector veins are moveable together within the housing outlet and cooperate there with to define a directionally adjustable discharge flow path for selective jet flow discharge in a sideward direction to produce a sideward thrust, or in a forwardly or rearwardly angled direction to respectively produce a reverse or forward propulsion thrust. In the sideward thrust position, the discharge flow path has a non-diverging cross-section and is isolated from the diverging fore-aft walls of the housing outlet.
U.S. Pat. No. 4,747,359, which issued to Ueno on May 31, 1988, discloses an apparatus for controlling the turn of a ship. When the right turn or left turn is set by operating one joystick lever, the bow thruster arrangement on the bow side generates the drift thrust in the rightward or leftward direction in accordance with the turning angular velocity on the bases of the operation of the joystick lever. At the same time, the propellers provided on the stern side are controlled so as to generate backward thrusts proportional to the absolute value of the turning angular velocity of the ship. The forward thrust of the ship which is caused due to the generation of the drift thrust by the bow thruster is suppressed. Thus, the ship is turned to the right or left around the stern as a rotational center at a predetermined speed with the position of the hull held.
U.S. Pat. No. 4,455,960, which issued to Aker on Jun. 26, 1984, describes a fluid valve actuated boat thruster. The boat thruster system includes a pump for drawing water through an inlet in the boat hull and for discharging water through first and second pipes connected to outlets located on either side of the hull. A valve is installed in each of the pipes to control the flow of water therethrough. The valves may be controlled by either an open or closed loop control system configured so as to prevent both outlet pipes from being closed at the same time during system operation. Each valve is preferably comprises of multiple veins, each of which is mounted for rotation about an off-center axis such that in the event of a valve control system failure, the water flow will cause the valve to open rather than close thereby preventing undesirable high pressure buildup in the system.
U.S. Pat. No. 4,412,500, which issued to Krautkremer on Nov. 1, 1983, describes a drive mechanism for ships or the like comprising a main propeller and an auxiliary mechanism. The drive mechanism for ships having at least one main propeller or the like is driveable by at least one main rotor and further has at least one driveable auxiliary mechanism, for example a maneuvering propeller. An energy producer is driveable by the main motor. A further motor is driven by the energy producer and arranged for driving the driveable auxiliary mechanism. An adjusting mechanism is provided for adjusting energy emitted by the energy producer or absorber by the further motor. A regulator adjusts the adjusting mechanism to a pre-selected energy output. The main motor and the auxiliary mechanism are sized such that in the higher part of the speed range of the main motor, the sum of the energy required to drive the propulsion means at that speed and simultaneously drive the auxiliary mechanism at that speed, exceed the output available from the main motor.
U.S. Pat. No. 5,501,072, which issued to Plancich et al on Mar. 26, 1996, discloses a combined centrifugal and paddle-wheel side thruster for boats. The propulsion mechanism for a boat includes an outlet conduit extending athwartships from a first outlet port to a second outlet port in the hull. A paddle-wheel impeller is mounted within the hull for rotation about an axis of rotation by a reversible motor. A circumferential paddle portion of the paddle-wheel impeller extends into an aperture defined centrally in the top wall of the outlet conduit. An inlet conduit extends athwartships from a first inlet port to a second inlet port, and intermediate thereof supplies water to the center of the paddle-wheel impeller. Water is discharged from the paddle-wheel impeller through one of the outlet ports, dependent upon the direction of rotation of the paddle-wheel impeller, to create thrust by a combined paddle-wheel and centrifugal pump action.
U.S. Pat. No. 4,531,920, which issued to Stricker on Jul. 30, 1985, describes a transverse waterjet propulsion system with auxiliary inlets and impellers. The waterjet propulsion system is disclosed having a transversely mounted engine driving one or more pumps with multiple inlets located so a great flow is available at low speed, subplaning operations, but at higher planing speeds, some inlets vent and a reduced flow is delivered to the pumps.
U.S. Pat. No. 4,423,696, which issued to Aker on Jan. 3, 1984, discloses an improved boat thruster system including swirl reducing veins. The system includes a pump for drawing water through an inlet in the boat hull and for discharging water through outlets on both sides of the hull. The improved system includes a plurality of substantially planer veins mounted in the water flow path proximate two said outlets. The veins function to reduce swirl angle components in the waterflow and thus increase thrust efficiency and prevent the ingestion of water borne debris into the outlets.
All of the United States patents identified and described above are hereby explicitly incorporated by reference in this description.
Known types of bow thrusters are commercially available from Vetus and are advertised as being available in various styles which provide various magnitudes of thrust and are constructed in many different sizes and shapes. Known types of stern thrusters are available from Dickson for boat lengths from 25 feet to 150 feet and with thrust magnitudes from 125 pounds to 1,500 pounds. Tunnel thrusters are available from Harbormaster in horsepower ratings from 150 horsepower to 3,000 horsepower and thrust magnitudes from 4,500 pounds to 66,000 pounds.
Many types of bow thrusters and stern thrusters are typically designed for marine vessels that are relatively large in size and, as a result, they are generally used on vessels larger than 25 feet in length. The use of standard bow thrusters and stern thrusters on smaller marine vessels is usually inhibited because of the relative costs of the conventional thrusters.
Marine vessels smaller than 25 feet in length can also present docking problems under certain circumstances. Most particularly, a youthful boat operator, an inexperienced adult operator of a boat may lack the necessary skills to maneuver a boat into a proper docking position by using only the primary propulsion system of the marine vessel. It would therefore be significantly beneficial if a relatively inexpensive maneuvering system could be incorporated in a marine vessel less than 25 feet in length so that an inexperienced or youthful boat operator could more easily maneuver the boat into a docking position. It would also be particularly beneficial if a control system could be provided for a maneuvering jet propulsion system that allows the boat operator to easily select the direction in which the boat is to move, turn, or rotate without having to translate that desired movement into a complicated series of actions in order to result in the desired movement of the vessel.